Rockwell Automation Publication 1769-UM021G-EN-P - October 2015
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Communicate over Networks
Chapter 6
Socket Interface with CompactLogix 5370 Controllers
CompactLogix 5370 controllers can use socket interfaces to communicate with
Ethernet devices that do not support the EtherNet/IP application protocol. The
socket interface is implemented via the Socket Object. CompactLogix 5370
controllers communicate with the Socket Object via MSG instructions. To
communicate with another device, you must understand the application protocol
of the other device.
CompactLogix 5370 controllers support up to 32 socket instances.
For more information on socket interface, see EtherNet/IP Socket Interface
Application Technique, publication
Quality of Service (QoS) and I/O Module Connections
CompactLogix 5370 controllers support Quality of Service (QoS) technology.
QoS lets the controller prioritize EtherNet/IP network traffic. By default, the
CompactLogix 5370 controllers are QoS-enabled. QoS can be disabled by
configuring a message instruction in the Logix Designer application.
Some EtherNet/IP devices do not support QoS technology unless the firmware
of the device is upgraded to a required minimum firmware revision level. For
example, the ControlLogix®? 1756-ENBT communication module must use
firmware revision 4.005 or later to support QoS technology.
To make sure communication between CompactLogix 5370 controllers and I/O
modules are maintained, verify that the EtherNet/IP devices use the minimum
firmware revision level of the product that is required to support QoS
technology.
For more information on the following, see Rockwell Automation
Knowledgebase Tech Note 66325 (the document is available at
http://www.rockwellautomation.com/knowledgebase/
):
•
Minimum firmware revision levels of EtherNet IP devices to support QoS
technology
•
Enable/disable QoS.
IMPORTANT
Keep the following in mind when using sockets with CompactLogix 5370 controllers:
•
A significant difference between CompactLogix 5370 controllers and other Logix5000 controllers
is the communication path. CompactLogix 5370 controllers do not require a separate EtherNet/IP
network communication module, for example, a 1756-EN2T module. In the case of the
CompactLogix 5370 controllers, the MSG is sent to the controller itself by using the path ‘1,0’.
•
All CompactLogix 5370 controllers must use unconnected MSG instructions for socket servers.
When you configure a message for a CompactLogix 5370 controller, make sure the Connected
checkbox on the Message Configuration dialog box is cleared.